I am back with quick post,
I was working on PowerApps forms, which using SharePoint Online List as DataSource. I have many Mulitline Text Box in that form and to save the data again and again from the PowerApps form.

What i noticed that when the form submitted after the first time save. Its losing some of the value.

After spending looking for the proper answer, what i find out that the Column property “Append Changes to Existing Text” was Yes.

So i turned this property into No, and then refresh the SharePoint DataSource.

This resolve the issue.